Sadie Sink’s ‘Spider-Man: Brand New Day’ Character Has Fans Convinced She’s Both Typhoid Mary and Jean Grey at the Same Time

Marvel has a long history of keeping its biggest casting secrets locked down until the very last moment, but the mystery surrounding Sadie Sink’s role in ‘Spider-Man: Brand New Day’ has taken that tradition to another level entirely. Months after her casting was confirmed, audiences got their first real trailer glimpse of the ‘Stranger Things’ star in action, and if anything, it only deepened the mystery rather than resolving it.

The speculation surrounding Sink’s character has split the internet straight down the middle, with two dominant fan theories emerging from the noise. One camp is firmly convinced she is stepping into the iconic role of Jean Grey, marking a seismic shift for the MCU’s mutant era. The other is equally persuasive, arguing that Typhoid Mary, a lesser-discussed but narratively fitting villain, makes far more sense given the grounded, street-level world of ‘Brand New Day’.

How Sadie Sink Landed Her ‘Spider-Man: Brand New Day’ Role

The story of how Sink came to be part of this film is almost as intriguing as the role itself. Sink revealed that she actually first learned about her casting through online speculation, saying the internet predicted she would be in the new ‘Spider-Man’ film before she even received an offer, and that sure enough, two days after seeing the chatter online, she was asked to join the project.

Deadline confirmed in March 2025 that Sink was set to star in the upcoming film, with her role described only as significant. Filming began in Glasgow, Scotland, in August, and director Destin Daniel Cretton later announced that production had officially wrapped.

When fans began speculating that her natural red hair pointed toward her playing Mary Jane Watson, Sink was coy about the theory, telling Entertainment Weekly that a lot of people forget hair color can change. That single deflection only poured more fuel onto the fire of an already raging fan debate, and Marvel has continued to stay firmly silent on the matter.

The Typhoid Mary Theory Gains Real Momentum

The Typhoid Mary angle is not simply a fringe theory. One prominent theory is that Marvel has cast Sink as a new version of Typhoid Mary, a mutant with dissociative identity disorder who has ties to the Hand, and the ‘Brand New Day’ trailer confirms that the Hand is indeed in the film, providing a direct narrative throughline for the possibility.

In the comics, Typhoid Mary was introduced in 1988 as a character shaped by childhood abuse, which resulted in the development of alternate personalities through dissociative identity disorder. The psychological strain of her past awakened latent psionic abilities of a mutant nature, and she grew into a formidable martial artist and street assassin who eventually caught Kingpin’s attention and became one of his most essential enforcers.

Fan reactions on social media have been passionate on this side of the debate. One person argued that Typhoid Mary fits the narrative ecosystem far better than a cosmic-level entity, noting that ‘Brand New Day’ is confirmed to be a more street-level story featuring the Punisher and Tombstone. Another pointed out that a pre-Xavier Jean Grey would not plausibly be this outright villainous, while a third questioned why Jean would remotely control a random civilian to drive a tank through New York, calling it firmly villain territory.

An alleged leaked image from the film that circulated recently, whose validity was questioned due to a Google Gemini watermark, appeared to show Sink alongside Jon Bernthal’s Punisher. The image reignited the Typhoid Mary debate because the character’s red bangs and hoodie bore resemblance to how the villain appeared in ‘Iron Fist’ Season 2.

Why the Jean Grey Case Remains the Strongest

Despite the compelling arguments for Typhoid Mary, the Jean Grey theory has not lost its grip on the majority of the fanbase. The ‘Brand New Day‘ trailer confirms that there is a telepath at play in the film. Spider-Man is shown battling an unseen enemy who hijacks other people’s consciousnesses, and this fight scene takes place in a high-security prison that matches shots of Sink’s character in captivity. Given that none of the film’s other confirmed villains possess telepathic abilities, many analysts believe Sink is almost certainly playing Jean Grey.

A previous report claimed that Sink is playing the MCU’s version of Jean Grey, which would mark the start of Marvel Studios’ X-Men era. The trailer shows her character strapped to a chair and wearing a green jacket, suggesting she may be a prisoner of the Department of Damage Control, which has been set up in the MCU as an anti-mutant organization targeting enhanced individuals.

The argument has also been made that the extraordinary level of secrecy surrounding Sink’s role is itself evidence pointing toward Jean Grey. Characters like Typhoid Mary, Shathra, and Firestar are deep-cut Marvel names who would not warrant this level of confidentiality. Marvel is rarely this secretive about major supporting characters in solo superhero films, which suggests the reveal must carry enormous weight for the broader universe.

If the Jean Grey rumors prove accurate, reports suggest Sink will return in ‘Avengers: Secret Wars’, with her character expected to play a pivotal role in setting up the MCU’s mutant-centric stories in Phase 7 and beyond.

What the Trailer Actually Shows

Stripping away the theory and looking purely at what the footage reveals, the evidence is genuinely layered. Sink’s character appears to function as a psychic puppet-master capable of controlling the bodies of others. Spider-Man neutralizes a tank that is out of control, only to find an innocent civilian trapped inside. A number of Damage Control agents are also shown reacting like puppets whose strings have been suddenly grabbed.

A leaked version of the trailer that surfaced earlier included a voiceover from Sink’s character that was stripped from the official cut. In the leak, the character can be heard addressing Spider-Man directly with the lines: “You’re a mess, Spider-Man. Don’t get in my way. Otherwise, it won’t just be your friends who don’t remember who Peter Parker is.” This dialogue confirmed that whoever Sink is playing, she has powers and full knowledge of Peter Parker’s identity.

Reports also emerged claiming that Sink’s character has a close relationship with the Punisher in the film. It has been theorized that Sink’s character and her explosive goals may have more to do with a feud against the Department of Damage Control than with any direct vendetta against Spider-Man, potentially framing the prison break as a message to a system that is actively hunting mutants.

A Villain or a Hero Pushed Too Far

The broader narrative context of ‘Brand New Day’ is what makes the identity question genuinely interesting from a storytelling perspective. The official synopsis confirms that four years have passed since the events of ‘No Way Home’, with Peter Parker living alone and having voluntarily erased himself from the lives of everyone he loves. As the demands on him intensify, the pressure sparks a physical evolution that threatens his existence, even as a new pattern of crimes brings one of the most powerful threats he has ever faced.

Marvel and Sony appear to be saving the official reveal of Sink’s character for the film’s release on July 31, 2026, leaving fans with months of theorizing still ahead of them. Whether she ultimately turns out to be a dormant mutant lashing out against those who imprisoned her or a street-level weapon serving darker interests, the performance itself is clearly positioned as the emotional centerpiece of the film.

Whether you are firmly in the Jean Grey camp or convinced that Typhoid Mary is the smarter narrative play, it is clear this is one of the most genuinely compelling identity mysteries Marvel has pulled off in years, so who do you think Sadie Sink is really playing in ‘Brand New Day’, and does the leaked dialogue change your theory at all?